As shown in FIG. 37, a conventional double-cassette-type magnetic recording-reproduction apparatus is provided with a tape transport mechanism 301, a driving circuit 302, a control circuit 303 and an input operation section 304. The tape transport mechanism 301 is used for driving cassette tapes, and the driving circuit 302 drives the tape transport mechanism 301. The control circuit 303, which has a microcomputer, controls the operations of the tape transport mechanism 301 by controlling the driving circuit 302. The input operation section 304 gives instructions to the control circuit 303 so that it conducts various operations.
The tape transport mechanism 301 includes the first and second mechanisms (hereinafter, referred to as mechanism sections) 310 and 330 for driving the first and second cassette tapes respectively. The first-mechanism section 310 is provided with the first-mechanism motor 311 and the first-mechanism solenoid 312 and the second-mechanism section 330 is provided with the second-mechanism motor 331 and the second-mechanism solenoid 332.
The input operation section 304 is provided with: a dubbing button 304a, the first-mechanism playback button 304b, the first-mechanism fast-forward button 304c, the first-mechanism rewind button 304d, the second-mechanism playback button 304e, the second-mechanism fast-forward button 304f, the second-mechanism rewind button 304g and a stop button 304h. In other words, this magnetic recording-reproduction apparatus has functions, such as playback, fast-forward, rewind and stop functions, for the first cassette tape that are carried out by the first-mechanism section 310 as well as having functions, such as playback, fast-forward, rewind and stop functions, for the second cassette tape that are carried out by the second-mechanism section 330. Further, the magnetic recording-reproduction apparatus also has a dubbing function by which a reproducing operation from the first cassette tape and a recording operation on the second cassette tape for the reproduced signals are carried out at the same time.
The respective buttons 304a through 304h have switches, and when the user operates any of these buttons 304a through 304h, a signal that is inherent to the button 304a-304h in question is inputted to the control circuit 303. Thus, the control circuit 303 controls the driving circuit 302, that is, the tape transport mechanism 301 so that the operation corresponding to the operated button 304a-304h is carried out.
As illustrated in FIG. 38, the tape transport mechanism 301 is assembled on a base plate 305. FIG. 38 shows the first-mechanism section 310 and the second-mechanism section 330 in their stopped state. In addition to the first-mechanism motor 311 (not shown) and the first-mechanism solenoid 312, the first-mechanism section 310 is provided with the first head board 313, the first over-stroke lever 314, the first over-stroke-lever spring 315, the first solenoid lever 316, and the first cam gear 317 that is urged to rotate clockwise.
Similarly, in addition to the second-mechanism motor 331 (not shown) and the second-mechanism solenoid 332, the second-mechanism section 330 is provided with the second head board 333, the second over-stroke lever 334, the second over-stroke-lever spring 335, the second solenoid lever 336, and the second cam gear 337 that is urged to rotate clockwise.
In the stopped state shown in FIG. 38, for example, when the user operates the first-mechanism playback button 304b, a signal corresponding to this button operation is inputted to the control circuit 303, and the first-mechanism section 310, which is controlled by the control circuit 303, carries out the following operations.
First, the first-mechanism motor 311 is activated, and after a lapse of a predetermined time allowed for the motor 311 to reach a predetermined rotating speed, the first-mechanism solenoid 312, which has received the signal from the control circuit 303, attracts a movable iron core 312a. Thus, the first solenoid lever 316, engaged with the movable iron core 312a, rotates clockwise to release the engagement between the engaging member 316a of the first solenoid lever 316 and the engaging member 317a of the first cam gear 317, thereby allowing the first cam gear 317 to start rotating clockwise.
As illustrated in FIG. 39, through this rotation, the cam 317c of the first cam gear 317 is engaged by the cam engaging shaft 314a of the first over-stroke lever 314, and the first over-stroke lever 314 is shifted in the direction of arrow C. At this time, the first head board 313, which is arranged to move integrally with the first over-stroke lever 314 through the first over-stroke-lever spring 315, is shifted in the direction of arrow C in the same manner.
Thereafter, the engaging member 316a of the first solenoid lever 316 that has returned to its original state after completion of power supply to the first-mechanism solenoid 312 is engaged by the engaging member 317b of the first cam gear 317 so that the first cam gear 317 is stopped in its rotation. Thus, the first-mechanism section 310 is brought into a driving state, that is, an operable state for playback.
Moreover, in the stopped state shown in FIG. 38, for example, when the user operates the second-mechanism playback button 304e, a signal corresponding to this button operation is inputted to the control circuit 303, and the second-mechanism section 330, which is controlled by the control circuit 303, carries out the following operations in the same manner as in the first-mechanism section 310.
First, the second-mechanism motor 331 is activated, and after a lapse of the predetermined time, the second-mechanism solenoid 332, which has received the signal from the control circuit 303, attracts a movable iron core 332a. Thus, the second solenoid lever 336, engaged with the movable iron core 332a, rotates clockwise to release the engagement between the engaging member 336a of the second solenoid lever 336 and the engaging member 337a of the second cam gear 337, thereby allowing the second cam gear 337 to start rotating clockwise.
As illustrated in FIG. 39, through this rotation, the cam 337c of the second cam gear 337 is engaged by the cam engaging shaft 334a of the second over-stroke lever 334, and the second over-stroke lever 334 is shifted in the direction of arrow C. At this time, the second head board 333, which is arranged to move integrally with the second over-stroke lever 334 through the second over-stroke-lever spring 335, is shifted in the direction of arrow C.
Thereafter, the engaging member 336a of the second solenoid lever 336 that has returned to its original state after completion of power supply to the second-mechanism solenoid 332 is engaged by the engaging member 337b of the second cam gear 337 so that the second cam gear 337 is stopped in its rotation. Thus, the second-mechanism section 330 is brought into a driving state, that is, an operable state for playback.
Furthermore, in the stopped state shown in FIG. 38, for example, when the user operates the dubbing button 304a, a signal corresponding to this button operation is inputted to the control circuit 303, and under control by the control circuit 303, the first-mechanism section 310 and the second-mechanism section 330 respectively carry out the same operations as those carried out when the first-mechanism and second-mechanism playback buttons are operated.
However, in the above-mentioned conventional double-cassette-type magnetic recording-reproduction apparatus, the first-mechanism section 310 and the second-mechanism section 330 are individually provided with dedicated driving sources, such as the first-mechanism motor 311 and the first-mechanism solenoid 312 as well as the second-mechanism motor 331 and the second-mechanism solenoid 332, and these driving sources have to be controlled individually by control signals from the control circuit 303. Consequently, the problems of the conventional arrangement are that a number of driving sources are required, that the number of parts increases, and that the cost of production is expensive.